Reclosable packages with tunable seal geometry

ABSTRACT

The present disclosure is directed to reclosable packages comprising a front wall, a rear wall, and a closure region proximate to an outer edge of the container opposite a bottom of the container. The closure region includes a plurality of seal regions forming a continuous seal between the front wall and the rear wall across a width of the package and at least one of the seal regions is nonlinear. The closure region further includes at least one unsealed region defined between the seal regions. In some reclosable packages, the application of an opening force proximate to the closure region is operable to break the continuous seal between the front wall and the rear wall across a width of the package. The seal geometry may be tuned to adjust the magnitude of opening force required.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 62/562,061 filed Sep. 22, 2017, the entire disclosure of whichis hereby incorporated by reference.

BACKGROUND

This disclosure relates to packaging articles. More specifically, thisdisclosure relates to resealable packaging articles and resealablepackaging articles including adhesives.

BACKGROUND

Convenience is a growing trend in the food packaging industry, withconsumers looking for packaging that can be easily handled and used.Reclosability in packaging not only offers consumer convenience, butalso provides longer shelf life of the packed product without the needto transfer contents into separate reclose packages, such as zipperedplastic bags or multi-piece rigid containers, for example. Conventionalreclose systems are limited in availability and have shortcomings suchas additional fabrication steps, poor processability, and a lack ofvariability in or control over opening forces and reclose pressures.Additionally, conventional reclose packages are usually coated waterbased acrylics and require lamination, die-cutting, or other secondaryprocessing steps. Hot melt adhesives based on styrenic block copolymers(SBC) eliminate some of the processing steps needed for coatedadhesives, but are difficult to process and may impart an unpleasantodor to the package.

SUMMARY

Accordingly, an ongoing need exists for reclosable packages—that is,packages with reclose and reopen functionality—with improvedprocessability and designs that enable streamlined and efficientmanufacture. A need further exists for package designs with tunableopening force and reclose pressure. A need further exists for foodpackages including adhesive compositions that enable reclose and reopenfunctionality, and that will not impart unpleasant odors to the food inthe package. A need especially exists for such packages with tunableopening force.

One or more of these needs are met by embodiments of the reclosablepackages of the present disclosure. The reclosabe packages of thepresent disclosure are structurally designed to have reclosable sealsthat can be integrated into the packaging. The reclosable seals involvedin packages of the present disclosure are versatile and can be modifiedto fit a variety of packaging sizes, shapes, and types. Additionally,the reclosable seals may be modified to tune or adjust the opening forceand reclose pressure of the seal. The reclosable packages may alsoinclude a multilayer film and the walls of the package may include themultilayer film. The package designs additionally allow for theintegration of adhesive compositions with relatively low SBC content andimproved odor into the reclosable seal.

According to one or more embodiments, a reclosable package comprises afront wall, a rear wall, and a closure region proximate to an outer edgeof the container opposite a bottom of the container. The closure regioncomprises a plurality of seal regions forming a continuous seal betweenthe front wall and the rear wall across a width of the package and atleast one of the seal regions is nonlinear. The closure region furthercomprises at least one unsealed region defined between the seal regions.

Additional features and advantages of the described embodiments will beset forth in the detailed description which follows, and in part will bereadily apparent to those skilled in the art from that description orrecognized by practicing the described embodiments, including thedetailed description which follows, the claims, as well as the appendeddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A schematically depicts a front view of a closure region of areclosable package, according to one or more embodiments of the presentdisclosure;

FIG. 1B schematically depicts a front view of a closure region of areclosable package, according to one or more embodiments of the presentdisclosure;

FIG. 1C schematically depicts a front view of a closure region of areclosable package, according to one or more embodiments of the presentdisclosure;

FIG. 2A schematically depicts a front perspective view of a reclosablepackage, according to one or more embodiments of the present disclosure;

FIG. 2B schematically depicts a front perspective view of a reclosablepackage, according to one or more embodiments of the present disclosure;

FIG. 3A schematically depicts a front perspective view of a reclosablepackage, according to one or more embodiments of the present disclosure;

FIG. 3B schematically depicts a front perspective view of the reclosablepackage of FIG. 3A after an opening force is applied, according to oneor more embodiments of the present disclosure;

FIG. 4 schematically depicts a cross-sectional view of a reclose filmthat includes three layers, according to one or more embodiments of thepresent disclosure;

FIG. 5 schematically depicts a cross-sectional view of another reclosefilm that includes 4 layers, according to one or more embodiments of thepresent disclosure;

FIG. 6A schematically depicts a cross-sectional view of the reclose filmof FIG. 4 adhered to a substrate, according to one or more embodimentsof the present disclosure;

FIG. 6B schematically depicts a cross-sectional view of the reclose filmof FIG. 6A in which the reclose film has been initially opened toactivate the reclose functionality of the reclose film, according to oneor more embodiments of the present disclosure;

FIG. 6C schematically depicts a cross-sectional view of the reclose filmof FIG. 6B in which the reclose film has been reclosed following initialopening of the reclose film, according to one or more embodiments of thepresent disclosure;

FIG. 6D schematically depicts a cross-sectional view of the reclose filmof FIG. 6C in which the reclose film has been reopened after beingreclosed, according to one or more embodiments of the presentdisclosure;

FIG. 7A schematically depicts a cross-sectional view of the reclose filmof FIG. 6A taken along reference line 7A-7A in FIG. 6A, according to oneor more embodiments of the present disclosure;

FIG. 7B schematically depicts a cross-sectional view of the reclose filmof FIG. 7A in which the reclose film has been initially opened toactivate the reclose functionality of the reclose film, according to oneor more embodiments of the present disclosure.

The embodiments set forth in the drawings are illustrative in nature andnot intended to be limiting to the claims. Moreover, individual featuresof the drawings will be more fully apparent and understood in view ofthe detailed description.

DETAILED DESCRIPTION

Embodiments of the present disclosure are directed to reclosablepackages. Reclosable packages of the present disclosure comprise a frontwall, a rear wall, and a bottom of the package. The closure regioncomprises a plurality of seal regions forming a continuous seal betweenthe front wall the rear wall across a width of the package.

As used herein, a “seal” refers to a closure of two or more items incontact, direct or indirect, that is tight enough to prevent passage ofunwanted materials through the point or surface of contact. A seal maybe mechanical or chemical in nature. For example, a mechanical sealmight consist of two rigid surfaces that are interlocked in such afashion as to prevent movement of the surfaces and movement between thesurfaces, such as zippers, snap lids, or similar devices. Examples ofchemical seals include solders, welds, adhesives, or similar substancesthat use a temperature, pressure, or a combination thereof to introducea chemical composition that prevents movement of two or more items. Theseal encompasses the items in contact, the surface or point of contact,and any other materials that might be at the surface or point ofcontact. The tightness of a seal may vary; hermetic seals,particle-tight seals, dust-tight seals, water-tight seals, liquid-tightseals, air-tight seals, wet gas-tight seals, or dry gas-tight seals arecontemplated.

Similarly, as used in this disclosure, two or more items can be said tobe “sealed” together when a surface of contact, direct or indirect,between the items is part of a seal. In some instances, the seal may bea result of the chemical or mechanical interactions between the items atthe surface. For example, meant to be illustrative and not limiting, iftwo objects are in adhering contact, and there is a seal at the surfaceof contact, the two objects can be said to be sealed together.

As used herein, the term “contact” can mean either direct contact orindirect contact. Direct contact refers to contact in the absence ofintervening material and indirect contact refers to contact through oneor more intervening materials. Items in direct contact touch each other.Items in indirect contact do not touch each other, but do touch anintervening material or series of intervening materials, where theintervening material or at least one of the series of interveningmaterials touches the other. Items in contact may be rigidly ornon-rigidly joined. Contacting refers to placing two items in direct orindirect contact. Items in direct contact may be said to directlycontact each other. Items in indirect contact may be said to indirectlycontact each other. It should be understood that, in some embodiments,when two items are “in contact” with one another, they are in directcontact with one another.

The term “polymer” refers to a polymeric compound prepared bypolymerizing monomers, whether of the same or a different type. Thegeneric term polymer thus embraces the term “homopolymer” usuallyemployed to refer to polymers prepared from only one type of monomer aswell as “copolymer” which refers to polymers prepared from two or moredifferent monomers. The term “block copolymer” refers to a polymercomprising two or more chemically distinct regions or segments (referredto as “blocks”). In some embodiments, these blocks may be joined in alinear manner, that is, a polymer comprising chemically differentiatedunits which are joined end-to-end. A “random copolymer” as used hereincomprises two or more polymers where each polymer may comprise a singleunit or a plurality of successive repeat units along the copolymer chainback bone. Even though some of the units along the copolymer chainbackbone exist as single units, these are referred to as polymersherein.

“Polyethylene” or “ethylene-based polymer” shall mean polymerscomprising greater than 50% by weight of units which have been derivedfrom ethylene monomer. This includes polyethylene homopolymers orcopolymers (meaning units derived from two or more comonomers). Commonforms of polyethylene known in the art include Low Density Polyethylene(LDPE); Linear Low Density Polyethylene (LLDPE); Ultra Low DensityPolyethylene (ULDPE); Very Low Density Polyethylene (VLDPE); single-sitecatalyzed Linear Low Density Polyethylene, including both linear andsubstantially linear low density resins (m-LLDPE); Medium DensityPolyethylene (MDPE); and High Density Polyethylene (HDPE). As usedherein, “ethylene/α-olefin random copolymer” is a random copolymercomprising greater than 50% by weight of units derived from ethylenemonomer.

The term “LDPE” may also be referred to as “high pressure ethylenepolymer” or “highly branched polyethylene” and is defined to mean thatthe polymer is partly or entirely homopolymerized or copolymerized inautoclave or tubular reactors at pressures above 14,500 psi (100 MPa)with the use of free-radical initiators, such as peroxides (see forexample U.S. Pat. No. 4,599,392, which is hereby incorporated byreference). LDPE resins typically have a density in the range of 0.916to 0.935 g/cm.

The term “LLDPE”, includes resin made using Ziegler-Natta catalystsystems as well as resin made using single-site catalysts, including,but not limited to, bis-metallocene catalysts (sometimes referred to as“m-LLDPE”) and constrained geometry catalysts, and resin made usingpost-metallocene, molecular catalysts. LLDPE includes linear,substantially linear or heterogeneous polyethylene copolymers orhomopolymers. LLDPEs contain less long chain branching than LDPEs andincludes the substantially linear ethylene polymers which are furtherdefined in U.S. Pat. Nos. 5,272,236, 5,278,272, 5,582,923 and 5,733,155;the homogeneously branched linear ethylene polymer compositions such asthose in U.S. Pat. No. 3,645,992; the heterogeneously branched ethylenepolymers such as those prepared according to the process disclosed inU.S. Pat. No. 4,076,698; and/or blends thereof (such as those disclosedin U.S. Pat. Nos. 3,914,342 or 5,854,045). The LLDPE resins can be madevia gas-phase, solution-phase or slurry polymerization or anycombination thereof, using any type of reactor or reactor configurationknown in the art.

The term “MDPE” refers to polyethylenes having densities from 0.926 to0.935 g/cc. “MDPE” is typically made using chromium or Ziegler-Nattacatalysts or using single-site catalysts including, but not limited to,bis-metallocene catalysts and constrained geometry catalysts.

The term “HDPE” refers to polyethylenes having densities greater thanabout 0.935 g/cc, which are generally prepared with Ziegler-Nattacatalysts, chrome catalysts or single-site catalysts including, but notlimited to, bis-metallocene catalysts and constrained geometrycatalysts.

The term “ULDPE” refers to polyethylenes having densities of 0.880 to0.912 g/cc, which are generally prepared with Ziegler-Natta catalysts,single-site catalysts including, but not limited to, bis-metallocenecatalysts and constrained geometry catalysts, and post-metallocene,molecular catalysts. The term “propylene-based polymer,” as used herein,refers to a polymer that comprises, in polymerized form, refers topolymers comprising greater than 50% by weight of units which have beenderived from propylene monomer. This includes propylene homopolymer,random copolymer polypropylene, impact copolymer polypropylene,propylene/α-olefin copolymer, and propylene/α-olefin copolymer. Thesepolypropylene materials are generally known in the art.

As used herein, the term “styrenic block copolymer” refers to a blockcopolymer that is produced from the polymerization of styrene monomerand at least one other comonomer. Additionally, as used herein,Molecular Weight Distribution (MWD) of a polymer is defined as thequotient Mw/Mn, where Mw is a weight average molecular weight of thepolymer and Mn is a number average molecular weight of the polymer.While melt index (I₂), as used herein, is a measure of melt flow rate ofa polymer as measured by ASTM D1238 at a temperature of 190° C. and a2.16 kg load.

Referring to FIG. 2A, according to one or more embodiments, a reclosablepackage 100 comprises a front wall 110, a rear wall 120, and a bottom130 of the reclosable package 100. The package may further comprise anouter edge 132 opposite the bottom 130. The bottom 130 may be the bottomedge of the front wall 110 and the rear wall 120 sealed to each other.In other embodiments, the bottom 130 may be a wall disposed between thefront wall 110 and rear wall 120. In one or more embodiments, thepackage may further comprise side edges 134 that may be longitudinallysealed. The package further comprises a closure region 150 proximate tothe outer edge 132.

In one or more embodiments, the closure region 150 comprises a pluralityof seal regions 160 and at least one unsealed region 170. A “sealregion” 160, as used in this disclosure, is a region in which the frontwall 110 and rear wall 120 are sealed together. Conversely, an “unsealedregion,” as used in this disclosure, is a region in which the front wall110 and rear wall 120 are not sealed together. In one or moreembodiments, the front wall 110 and the rear wall 120 are spaced apartthroughout the entirety of the unsealed region. This gap may comprisespace, air, other gases, or other fluids. In other embodiments, anunsealed region may comprise areas where the front wall and rear wallare in contact, but not sealed together.

In one or more embodiments, the plurality of seal regions 160 maycooperate to form a continuous seal between the front wall 110 and therear wall 120 extending across a width w₁ of the reclosable package 100.In one or more embodiments, at least one of the seal regions 160 isnonlinear. As used in herein, “nonlinear” refers to an object that isnot a straight line or not in the shape of a straight line.Additionally, as used herein in the context of multiple objects,“nonlinear” may refer to an organization of objects that are notarranged in a straight line. In one or more embodiments, the closureregion 150 further comprises at least one unsealed region 170 definedbetween the seal regions 160.

For illustrative purposes, the closure regions 150 of several example,but not intended to be limiting, reclosable packages 100 with variousseal geometries are isolated and presented in FIGS. 1A-1C. The term“seal geometry,” as used herein, refers to the shape, size, overlay,relative configuration, and patterns of the seal regions 160 within theclosure region 150. Referring to FIG. 1A, a plurality of seal regions160 are disposed within the closure region 150. The closure region 150extends up to a seal region 160 furthest from the bottom 130, sealregion 160 a, and down to a seal region 160 closest to the bottom, sealregion 160 b, across a width w, defined between side edges 134. Theclosure region 150 further comprises unsealed regions 170 definedbetween the seal regions 160. Still referring to FIG. 1A, the labeledunsealed region 170 is defined by the upper and lower boundaries of theclosure region 150 and the seal regions 160 c, 160 d.

Referring to FIG. 1B, in one or more embodiments, the closure region 150further comprises two or more seal lines 180. As used herein, a sealline 180 is a linear continuous seal between the front wall 110 and therear wall 120, across the width w₂ of the closure region 150. In one ormore embodiments, the two or more seal lines 180 comprise an upper sealline 182, the seal line 180 farthest from the bottom 130, and a lowerseal line 184, the seal line 180 closest to the bottom 130. In suchembodiments, the at least one nonlinear seal region 160 is disposedbetween the upper seal line 182 and the lower seal line 184. In one ormore embodiments, a theoretical line can be drawn parallel to the bottom130, through the closure region 150, not intersecting with any seallines 180 that passes through seal regions 160 and at least one unsealedregion 170.

Referring to the embodiment of FIG. 1C, the closure region 150 areclosable package 100 comprises three seal lines 180, one of which isthe upper seal line 182 and a second of which is the lower seal line184. The closure region 150 further comprises a plurality of sealregions 160 and unsealed regions 170 disposed between the upper sealline 182 and the lower seal line 184.

Having described various example embodiment seal geometries in referenceto the seal geometry profiles of FIGS. 1A-1C, it is emphasized thatthese examples are not meant to be limiting and are intended to clarifythe description of the seal geometry of one or more embodimentreclosable packages 100. Further description will now be given on thereclosable packages 100 comprising the seal geometries previouslydescribed.

Referring again to FIG. 2A, in one or more embodiments, a reclosablepackage 100 comprises a closure region 150 proximate to the outer edge132 as illustrated in FIG. 1A. Referring to FIG. 2B, in one or moreembodiments, a reclosable package 100 comprises a closure region 150that may comprise two or more seal lines 180. The two or more seal lines180 may comprise an upper seal line 182 and a lower seal line 184. Aplurality of seal regions 160 and a plurality of unsealed regions 170may be disposed between the upper seal line 182 and the lower seal line184.

Referring to FIG. 3A, in one or more embodiments, a reclosable package100 may further comprise a border seal 138. The border seal 138 is acontiguous region in which the front wall 110 is sealed to the rear wall120 that may extend from the seal edge 134 to a border edge 136. In oneor more embodiments, the border seal 138 may extend past the bottom 130,surround the bottom 130 and extend along the length of a second sealedge 134. In one or more embodiments, the application of an openingforce proximate to the closure region 150 is operable to separate atleast part of the front wall 110 from the rear wall 120, breaking thecontinuous seal between the front wall 110 and the rear wall 120 acrossa width Iii₂ of the closure region 150. Referring to FIG. 3B, in one ormore embodiments, after portions of the front wall 110 and rear wall 120separate along width w₂, as described herein, the front wall 110 andrear wall 120 remain sealed along the border seal 138.

In one or more embodiments, the front wall 110, the rear wall 120, orcombinations thereof may comprise a reclose film. In other embodiments,the closure region 150 may comprise a strip of reclose film disposedbetween the front wall 110 and the rear wall 120. As used in the presentdisclosure, a reclose film is a multilayer film comprising at leastthree layers: an A layer, a B layer, and a C layer. Layer A may be asealant layer, Layer B may be a reclose layer and include thecomposition disclosed herein and subsequently described, and Layer C mayinclude a support material, such as a polyolefin or other supportmaterial, for example, or may be a sealant layer. Referring to FIG. 4,Layer B is positioned proximal to Layer A with a top facial surface 214of Layer B in adhering contact with a bottom facial surface 222 of LayerA. A top facial surface 224 of Layer C is in adhering contact with thebottom facial surface 232 of Layer B.

In one or more embodiments, the composition of Layer B comprises anethylene/α-olefin random copolymer, a styrenic block copolymer, atackifier, and an oil. The adhesive composition of Layer B may alsoprovide the reclose and reopen functionality to the reclose film orreclosable package. Additionally, in some embodiments, the adhesivecomposition does not negatively affect the quality of the packagecontents. For example, in one or more conventional reclosable packages,compositions present in the package may impart an unpleasant odor to thepackage contents. In one or more embodiments, the reclosable packagedoes not affect the aroma, smell, odor, or other olfactory properties ofthe package contents. The adhesive compositions of the presentdisclosure include reduced concentrations of styrenic block copolymerscompared to conventional reclose films. Therefore, the adhesivecompositions of the present disclosure and the multilayer films andpackages made therewith may provide reclosability to food packagingfilms without negatively impacting odor or taste of the packagecontents.

The ethylene/α-olefin random copolymer of the compositions may be acopolymer of ethylene comonomer and at least one α-olefin comonomer(i.e., alpha olefin comonomer). Suitable α-olefin comonomers may includethose containing 3 to 20 carbon atoms (C₃-C₂₀ α-olefins). In someembodiments, the α-olefin comonomer may be a C₃-C₂₀ α-olefin, a C₃-C₁₂α-olefin, a C₃-C₁₀ α-olefin, a C₃-C₈ α-olefin, a C₄-C₂₀ α-olefin, aC₄-C₁₂ α-olefin, a C₄-C₁₀ α-olefin, or a C₄-C₈ α-olefin. In one or moreembodiments, the ethylene/α-olefin random copolymer may be a copolymerof ethylene comonomer and one or more co-monomers selected frompropylene, 1-butene, 3-methyl-1-butene, 1-pentene, 3-methyl-1-pentene,4-methyl-1-pentene, 1-hexene, 1-septene, 1-octene, 1-nonene, 1-decene,1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.In one or more embodiments, the ethylene/α-olefin random copolymer maybe a copolymer of ethylene comonomer and 1-hexene comonomer. In one ormore embodiments, the ethylene/α-olefin random copolymer may be anethylene/octene copolymer that may be made from ethylene comonomer andoctene comonomer.

A weight percent of ethylene monomer units in the ethylene/α-olefinrandom copolymer may be greater than 50 wt. % in one or moreembodiments, or greater than or equal to 55 wt. % in other embodiments,or greater than or equal to 60 wt. % in yet other embodiments, orgreater than or equal to 65 wt. % in yet other embodiments. In someembodiments, the ethylene/α-olefin random copolymer may include fromgreater than 50 wt. % to 70 wt. %, from greater than 50 wt. % to 65 wt.%, from greater than 50 wt. % to 60 wt. %, from 55 wt. % to 70 wt. %,from 55 wt. % to 65 wt. %, from 55 wt. % to 60 wt. %, from 60 wt. % to70 wt. %, from 60 wt. % to 65 wt. %, or from 65 wt. % to 70 wt. %ethylene monomer units. Conversely, a weight percent of the α-olefincomonomer in the first polyethylene resin may be less than 50 wt. % inone or more embodiments, or less than or equal to 45 wt. % in otherembodiments, or less than or equal to 40 wt. % in yet other embodiments,or less than or equal to 35 wt. % in yet other embodiments.

The ethylene/α-olefin random copolymer may have a density of less thanor equal to 0.890 grams per centimeter cubed (g/cm³). In someembodiments, the ethylene/α-olefin random copolymer may have a densitythat is less than or equal to 0.880 g/cm³, or even less than 0.87 g/cm³.The density of the ethylene/α-olefin random copolymer is measured inaccordance with ASTM D792. In one or more embodiments, theethylene/α-olefin random copolymer may have a density of from 0.850g/cm³ to 0.890 g/cm³. In one or more embodiments, the ethylene/α-olefinrandom copolymer may have a density of from 0.850 g/cm³ to 0.880 g/cm³,from 0.850 g/cm³ to 0.870 g/cm³, from 0.860 g/cm³ to 0.890 g/cm³, or0.860 g/cm³ to 0.880 g/cm³.

The ethylene/α-olefin random copolymer may have a melting point of lessthan or equal to 100 degrees Celsius (° C.). For example, in someembodiments, the ethylene/α-olefin random copolymer may have a meltingpoint of less than or equal to 95° C., less than or equal to 90° C.,less than or equal to 80° C., or even less than or equal to 75° C. Insome embodiments, the ethylene/α-olefin random copolymer may have amelting point of greater than room temperature, such as greater than orequal to 30° C. or even greater than or equal to 40° C. In someembodiments, the ethylene/α-olefin random copolymer may have a meltingpoint of from 30° C. to 100° C., from 30° C. to 95° C., from 30° C. to90° C., from 30° C. to 80° C., from 30° C. to 75° C., from 40° C. to100° C., from 40° C. to 95° C., from 40° C. to 90° C., from 40° C. to80° C., or from 40° C. to 75° C.

The ethylene/α-olefin random copolymer may have a melt index (I₂), whichis measured according to ASTM D1238 at 190° C. and 2.16 kg load, of from0.2 grams per 10 minutes (g/10 min) to 8.0 g/10 min, from 0.2 g/10 minto 5.0 g/10 min, from 0.2 g/10 min to 3.0 g/10 min, from 0.2 g/10 min to1.5 g/10 min, from 0.2 g/10 min to 1.0 g/10 min, from 0.5 g/10 min to8.0 g/10 min, from 0.5 g/10 min to 5.0 g/10 min, from 0.5 g/10 min to3.0 g/10 min, from 0.5 g/10 min to 1.5 g/10 min, from 0.5 g/10 min to1.0 g/10 min, from 1.0 g/10 min to 8.0 g/10 min, from 1.0 g/10 min to5.0 g/10 min, from 1.0 g/10 min to 3.0 g/10 min, or from 3.0 g/10 min to8.0 g/10 min. In one or more embodiments, the ethylene/α-olefin randomcopolymer may have a melt index (I₂) of from 0.2 g/10 min to 8.0 g/10min. In one or more other embodiments, the ethylene/α-olefin randomcopolymer may have a melt index (I₂) of from 0.5 g/10 min to 1.5 g/10min.

The ethylene/α-olefin random copolymer may have a molecular weightdistribution (MWD or Mw/Mn) of from 1.0 to 3.5, from 1.0 to 3.0, from1.0 to 2.5, from 1.0 to 2.2, from 1.0 to 2.0, from 1.3 to 3.5, from 1.3to 3.0, from 1.3 to 2.5, from 1.3 to 2.2, from 1.3 to 2.0, from 1.7 to3.5, from 1.7 to 3.0, from 1.7 to 2.5, from 1.7 to 2.2, or from 1.7 to2.0. In one or more embodiments, the ethylene/α-olefin random copolymermay have a MWD of from 1.0 to 3.5. Mw is the weight average molecularweight and Mn is the number average molecular weight, both of which maybe measured by gel permeation chromatography (GPC).

The dynamic melt viscosity of the ethylene/α-olefin random copolymer maybe measured using Dynamic Mechanical Spectroscopy (DMS), which isdescribed subsequently in this disclosure. In some embodiments, theethylene/α-olefin random copolymer may have a ratio of the dynamic meltviscosity at 0.1 radians per second to the dynamic melt viscosity at 100radians per second of less than or equal to 20 at a temperature of 110°C. as determined by DMS. In some embodiments, the ethylene/α-olefinrandom copolymer may have a ratio of the dynamic melt viscosity at 0.1radians per second to the dynamic melt viscosity at 100 radians persecond of less than or equal to 15 at a temperature of 130° C. asdetermined by DMS. In some embodiments, the ethylene/α-olefin randomcopolymer may have a ratio of the dynamic melt viscosity at 0.1 radiansper second to the dynamic melt viscosity at 100 radians per second ofless than or equal to 10 at a temperature of 150° C. as determined byDMS.

The ethylene/α-olefin random copolymer may be made by gas-phase,solution-phase, or slurry polymerization processes, or any combinationthereof, using any type of reactor or reactor configuration known in theart, e.g., fluidized bed gas phase reactors, loop reactors, continuousstirred tank reactors, batch reactors in parallel, series, or anycombinations thereof. In some embodiments, gas or slurry phase reactorsare used. In some embodiments, the ethylene/α-olefin random copolymer ismade in a gas-phase or slurry process such as that described in U.S.Pat. No. 8,497,330, which is herein incorporated by reference in itsentirety. The ethylene/α-olefin random copolymer may also be made by ahigh pressure, free-radical polymerization process. Methods forpreparing the ethylene/α-olefin random copolymer by high pressure, freeradical polymerization can be found in U.S. 2004/0054097, which isherein incorporated by reference in its entirety, and can be carried outin an autoclave or tubular reactor as well as any combination thereof.Details and examples of a solution polymerization of ethylene monomerand one or more α-olefin comonomers in the presence of a Ziegler-Nattacatalyst are disclosed in U.S. Pat. Nos. 4,076,698 and 5,844,045, whichare incorporated by reference herein in their entirety. The catalystsused to make the ethylene/α-olefin random copolymer described herein mayinclude Ziegler-Natta, metallocene, constrained geometry, single sitecatalysts, or chromium-based catalysts.

Exemplary suitable ethylene/α-olefin random copolymers may include, butmay not be limited to, AFFINITY™ EG 8100 ethylene/α-olefin randomcopolymer and ENGAGE™ 8842 ethylene/α-olefin copolymer supplied by TheDow Chemical Company, Midland, Mich.

The pressure sensitive adhesive composition may include from 30 wt. % to65 wt. % ethylene/α-olefin random copolymer. For example, in someembodiments, the adhesive composition may include from 30 wt. % to 55wt. %, from 33 wt. % to 65 wt. %, or from 33 wt. % to 55 wt. %ethylene/α-olefin random copolymer.

As previously discussed, the adhesive composition includes a styrenicblock copolymer. The styrenic block copolymer contains from greater than1 wt. % to less than 50 wt. % styrene. In some embodiments, the styrenicblock copolymer may include from 10 wt. % styrene to less than 50 wt. %styrene. The styrene monomer may be styrene or a styrene derivative,such as alpha-methyl styrene, 4-methylstyrene, 3,5-diethylstyrene,2-ethyl-4-benzylstyrene, 4-phenylstyrene, or mixtures thereof. In oneembodiment, the styrene monomer is styrene. Various olefin or diolefin(diene) comonomers are contemplated as suitable for polymerizing withthe styrene. The olefin comonomer may comprise C₃-C₂₀ α-olefins. Thediolefin comonomers may include various C₄-C₂₀ olefins such as1,3-butadiene, 1,3-cyclohexadiene, isoprene, 1,3-pentadiene,1,3-hexadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene,2-methyl-1,3 pentadiene, 3-methyl-1,3-pentadiene,4-methyl-1,3-pentadiene, and 2,4-hexadiene, or combinations thereof.

Examples of suitable styrenic block copolymers may include, but are notlimited to, styrene-isoprene-styrene block copolymers (SIS),styrene-butadiene-styrene block copolymers (SBS),styrene-ethylene/butylene-styrene block copolymers (SEBS),styrene-isobutylene-styrene block copolymers (SIBS),styrene-ethylene-propylene-styrene block copolymers (SEPS), and mixturesthereof. Examples of styrenic block copolymers may include, but are notlimited to, materials commercially available under the tradename“KRATON” such as KRATON D1161, KRATON D1118, KRATON G1657, and the like,available from Kraton Corp., Houston, Tex. or materials commerciallyavailable under the trade name “Vector” such as 4113A, 4114A, 4213A, andthe like, available from Dexco Polymers, Houston, Tex.

The styrenic block copolymer includes less than 50 wt. % styrene. Forexample, in some embodiments, the stryrenic block polymer may includeless than or equal to 45 wt. %, less than or equal to 40 wt. %, lessthan or equal to 35 wt. %, less than or equal to 30 wt. %, or even lessthan or equal to 25 wt. % styrene. In some embodiments, the styrenicblock copolymer may have from greater than or equal to 1 wt. % to lessthan 50 wt. % styrene. In other embodiments, the styrenic blockcopolymer may have from 5 wt. % to less than 50 wt. %, from 10 wt. % toless than 50 wt. %, from 15 wt. % to less than 50 wt. %, from 20 wt. %to less than 50 wt. %, from 1 wt. % to 45 wt. %, from 1 wt. % to 40 wt.%, from 1 wt. % to 35 wt. %, from 1 wt. % to 30 wt. %, from 1 wt. % to25 wt. %, from 5 wt. % to less than 50 wt. %, from 5 wt. % to 45 wt. %,from 5 wt. % to 40 wt. %, from 5 wt. % to 35 wt. %, from 5 wt. % to 30wt. %, from 5 wt. % to 25 wt. %, from 10 wt. % less than 50 wt. %, from10 wt. % to 45 wt. %, from 10 wt. % to 40 wt. %, from 10 wt. % to 35 wt.%, from 10 wt. % to 30 wt. %, from 10 wt. % to 25 wt. %, from 15 wt. %to less than 50 wt. %, from 15 wt. % to 45 wt. %, from 15 wt. % to 40wt. %, from 15 wt. % to 35 wt. %, from 15 wt. % to 30 wt. %, or from 15wt. % to 25 wt. % styrene. In some embodiments, the styrenic blockcopolymer including less than 50 wt. % styrene may include an amount ofnon-styrenic copolymer that is sufficient to interact with thetackifier. In some embodiments, the styrenic block copolymer may be SISand the styrenic block copolymer may include from 15 wt. % to 25 wt. %styrene. In other embodiments, the styrenic block copolymer may be SISand may include from 20 wt. % to 25 wt. % styrene.

The compositions disclosed herein may include from 10 wt. % to 35 wt. %styrenic block copolymer based on the total weight of the composition.For example, in some embodiments, the compositions may include from 10wt. % to 30 wt. % styrenic block copolymer based on the total weight ofthe composition.

The tackifier may be a resin added to the compositions disclosed hereinto reduce the modulus and increase the surface adhesion of thecompositions compared to the compositions without the tackifier. In someembodiments, the tackifier may be a hydrocarbon tackifier. The tackifiermay include, but is not limited to, non-hydrogenated aliphatic C₅ (fivecarbon atoms) resins, hydrogenated aliphatic C₅ resins, aromaticmodified C₅ resins, terpene resin, hydrogenated C₉ resins, orcombinations thereof. In some embodiments, the tackifier may be selectedfrom the group consisting of a non-hydrogenated aliphatic C₅ resin and ahydrogenated aliphatic C₅ resin. In some embodiments, the compositionmay include a plurality of tackifiers.

In some embodiments, the tackifier may have a density from 0.92 g/cm³ to1.06 g/cm³. The tackifier may exhibit a Ring and Ball softeningtemperature of from 80° C. to 140° C., from 85° C. to 130° C., from 90°C. to 120° C., from 90° C. to 110° C., or from 91° to 100° C. The Ringand Ball softening temperature may be measured in accordance with ASTM E28. In some embodiments, the tackifier may exhibit a melt viscosity ofless than 1000 Pascal second (Pa-s) at 175° C. For example, in otherembodiments, the tackifier may exhibit a melt viscosity of less than orequal to 500 Pa-s, less than or equal to 200 Pa-s, less than or equal to100 Pa-s, or even less than or equal to 50 Pa-s at 175° C. Further, insome embodiments, the tackifier may exhibit a melt viscosity greaterthan or equal to 1 Pa-s or greater than or equal to 5 Pa-s at 175° C. Ina some embodiments, the tackifier may exhibit a melt viscosity from 1Pa-s to less than 100 Pa-s, or to less than 50 Pa-s at 175° C. The meltviscosity of the tackifier may be determined using dynamic mechanicalspectroscopy (DMS).

The C₅ resin for a “C₅ tackifier” may be obtained from C₅ feedstockssuch as pentenes and piperylene. The terpene resin for a tackifier maybe based on pinene and d-limonene feedstocks. Examples of suitabletackifiers may include, but are not limited to, tackifiers sold underthe tradename PICCOTAC, REGALITE, REGALREZ, and PICCOLYTE, such asPICCOTAC 1100, PICCOTAC 1095, REGALITE R1090, and REGALREZ 11126,available from The Eastman Chemical Company, and PICCOLYTE F-105 fromPINOVA.

The compositions disclosed herein may include from 20 wt. % to 40 wt. %tackifier. In some embodiments, the compositions may have from 20 wt. %to 35 wt. %, from 20 wt. % to 30 wt. %, from 25 wt. % to 40 wt. %, from25 wt. % to 35 wt. %, or from 25 wt. % to 30 wt. % tackifier based onthe total weight of the composition.

As previously discussed, the compositions disclosed herein may alsoinclude an oil. In some embodiments, the oil may include greater than 95mole % aliphatic carbon compounds. In some embodiments, the oil mayexhibit a glass transition temperature for the amorphous portion of theoil that is less than −70° C. In some embodiments, the oil can be amineral oil. Examples of suitable oils may include, but are not limitedto, mineral oil sold under the tradenames HYDROBRITE 550 (Sonneborn),PARALUX 6001 (Chevron), KAYDOL (Sonneborn), BRITOL 50T (Sonneborn),CLARION 200 (Citgo), CLARION 500 (Citgo), or combinations thereof. Insome embodiments, the oil may comprise a combination or two or more oilsdescribed herein. The compositions disclosed herein may include fromgreater than 0 wt. % to 8 wt. % oil. For example, in some embodiments,the compositions may include from greater than 0 wt. % to 7 wt. %, from3 wt. % to 8 wt. %, from 3 wt. % to 7 wt. %, from 5 wt. % to 8 wt. %, orfrom 5 wt. % to 7 wt. % oil based on the total weight of thecomposition.

The present compositions may optionally include one or more additives.Examples of suitable additives may include, but are not limited to,antioxidants, ultraviolet absorbers, antistatic agents, pigments,viscosity modifiers, anti-block agents, release agents, fillers,coefficient of friction (COF) modifiers, induction heating particles,odor modifiers/absorbents, and any combination thereof. In anembodiment, the compositions further comprise one or more additionalpolymers. Additional polymers include, but are not limited to,ethylene-based polymers and propylene-based polymers.

In some embodiments, the compositions disclosed herein may include from30 wt. % to 65 wt. % ethylene/α-olefin random copolymer, from 10 wt. %to 35 wt. % styrenic block copolymer, from 20 wt. % to 40 wt. %tackifier, and from greater than 0 wt. % to 8 wt. % oil. In otherembodiments, the compositions may include from 33 wt. % to 55 wt. %ethylene/α-olefin random copolymer, from 10 wt. % to 30 wt. % styrenicblock copolymer, from 25 wt. % to 30 wt. % tackifier, and from 5 wt. %to 7 wt. % oil.

In some embodiments, the compositions may have an overall density ofless than or equal to 0.930 g/cm³, or less than or equal to 0.920 g/cm³.In some embodiments, the compositions may have an overall density offrom 0.880 g/cm³ to 0.930 g/cm³, from 0.880 g/cm³ to 0.920 g/cm³, from0.890 g/cm³ to 0.930 g/cm³, or from 0.89 g/cm³ to 0.92 g/cm³.

In some embodiments, the compositions may exhibit an overall melt index(I₂) of from 2 grams per 10 minutes (g/10 min) to 15 g/10 min. Forexample, in some embodiments, the compositions may exhibit an overallmelt index (I₂) of from 2 g/10 min to 14 g/10 min, from 2 g/10 min to 12g/10 min, from 2 g/10 min to 10 g/10 min, from 3 g/10 min to 15 g/10min, from 3 g/10 min to 14 g/10 min, from 3 g/10 min to 12 g/10 min,from 3 g/10 min to 10 g/10 min, from 5 g/10 min to 15 g/10 min, from 5g/10 min to 14 g/10 min, from 5 g/10 min to 12 g/10 min, from 5 g/10 minto 10 g/10 min, from 7 g/10 min to 15 g/10 min, from 7 g/10 min to 14g/10 min, from 7 g/10 min to 12 g/10 min, or from 7 g/10 min to 10 g/10min. The overall melt index (I₂) is determined according to ASTM D1238at 190° C. and 2.16 kg load.

The dynamic melt viscosity may be determined using Dynamic MechanicalSpectroscopy (DMS) at a various testing temperatures and testingfrequency. The compositions may exhibit a dynamic melt viscosity of from1,000 Pa-s to 1,400 Pa-s measured using DMS at a temperature of 190° C.and a frequency of 1 Hz. The compositions may exhibit a dynamic meltviscosity of from 3,200 Pa-s to 4,000 Pa-s measured using DMS at atemperature of 150° C. and a frequency of 1 Hz. The compositions mayexhibit a dynamic melt viscosity of from 7,400 Pa-s to 7,800 Pa-smeasured using DMS at a temperature of 130° C. and a frequency of 1 Hz.The compositions may exhibit a dynamic melt viscosity of from 12,400Pa-s to 17,200 Pa-s measured using DMS at a temperature of 110° C. and afrequency of 1 Hz.

In some embodiments, the compositions disclosed herein may exhibit amelt temperature of less than or equal to 100° C., less than or equal to90° C., or even less than or equal to 80° C. In some embodiments, thecompositions may exhibit a melt temperature of from 60° C. to 100° C.,from 60° C. to 90° C., from 60° C. to 80° C., from 70° C. to 100° C., orfrom 70° C. to 90° C. In some embodiments, the compositions may exhibitno melting peaks above 100° C.

The compositions may exhibit an initial internal cohesion force of lessthan or equal to 40 newtons/inch (N/in), less than or equal to 37 N/in,less than 35 N/in, or even less than 30 N/in after being heat sealed ata heat sealing temperature of 150° C. The initial internal cohesionforce of the compositions may be determined according to the test methodfor peel strength described herein. In some embodiments, thecompositions may exhibit an initial internal cohesion force of from 25N/in to 40 N/in, from 25 N/in to 37 N/in, from 25 N/in to 35 N/in, from27 N/in to 40 N/in, from 27 N/in to 37 N/in, from 27 N/in to 35 N/in,from 30 N/in to 40 N/in, from 30 N/in to 37 N/in, or from 30 N/in to 35N/in after being heat sealed at a heat sealing temperature of 130° C.

In some embodiments, the compositions may exhibit a reclose peeladhesion force of greater than or equal to 1.0 N/in after being heatsealed at a heat seal temperature of 150° C., initially opened, andafter experiencing at least 4 reclose-reopen cycles. In someembodiments, the compositions may exhibit a reclose peel adhesion forceof greater than or equal to 1.5 N/in, greater than or equal to 2.0 N/in,or even greater than 2.5 N/in after being heat sealed at a heat sealtemperature of 150° C., initially opened, and after experiencing atleast 4 reclose-reopen cycles. In some embodiments, the compositions mayexhibit a reclose peel adhesion force of from 2.0 N/in to 10.0 N/in,from 2.0 N/in to 7.0 N/in, from 2.0 N/in to 5.0 N/in, from 2.5 N/in to10.0 N/in, from 2.5 N/in to 7.0 N/in, or from 2.5 N/in to 5.0 N/in afterbeing heat sealed at a heat seal temperature of 150° C., initiallyopened, and after experiencing at least 4 reclose-reopen cycles.

The compositions disclosed herein may be compounded using a single stagetwin-screw extrusion process or any other conventional blending orcompounding process.

The compositions disclosed herein may be incorporated into a multilayerfilm, which may provide reclose functionality to packaging made from themultilayer film. The multilayer film may include at least three layers:a sealing layer forming a facial surface of the multilayer film, areclose layer in adhering contact with the sealing layer, and at leastone supplemental layer in adhering contact with the reclose layer. Thesealing layer may seal the multilayer film to a substrate, such as asurface of a container, another flexible film, or to itself, forexample. The reclose layer, once activated by exerting an initialopening force on the multilayer film, may provide reclose/reopenfunctionality to the multilayer film. At least one supplemental layermay provide structural support to the multilayer film or may provide anadditional sealing layer.

Referring to FIG. 4, the reclose film 200 is illustrated that includesat least three layers: Layer A, Layer B, and Layer C. The reclose film200 will be described relative to an embodiment having three layers;however, the multilayer film may have more than three layers, such asfour, five, six, seven, eight, or even more than 8 layers. For example,referring to FIG. 5, the multilayer film may have 4 layers: Layer A,Layer B, Layer C, and Layer D. Reclose films with more than 4 layers arealso contemplated.

Referring again to FIG. 4, the reclose film 200 may have a film topfacial surface 202 and a film bottom facial surface 204. Similarly, eachof the layers A, B, and C may have opposing facial surfaces, such as atop facial surface and a bottom facial surface. As used in thisdisclosure, the term “top” refers to the facial surface of themultilayer oriented toward the Layer A side of the reclose film 200, andthe term “bottom” refers to the opposite side of the reclose film 200oriented away from the Layer A side of the reclose film 200.

Layer A may have a top facial surface 212 and a bottom facial surface214. The top facial surface 212 of Layer A may be the film top facialsurface 202 of the reclose film 200. The bottom facial surface 214 ofLayer A may be in adhering contact with the top facial surface 222 ofLayer B.

Layer A is a sealing layer that includes a sealing composition capableof sealing the film top facial surface 202 of the reclose film 200 to asurface of a substrate or to itself. For example, in some embodiments,the sealing composition may be a heat sealing composition. In someembodiments, the sealing composition may be capable of hermeticallysealing the film top facial surface 202 of the reclose film 200 to asurface of a substrate or to itself. In some embodiments, the sealingcomposition may include a polyolefin. For example, in some embodiments,the sealing composition of Layer A may include at least one of lowdensity polyethylene (LDPE), linear low density polyethylene (LLDPE),ultra-low density polyethylene (ULDPE), ethylene vinyl acetate (EVA),ionomers, polyolefin elastomers, other sealing composition, orcombinations of these. Examples of sealing compositions may include, butare not limited to, AFFINITY™ polyolefin elastomer supplied by The DowChemical Company, Midland, Mich. In some embodiments, Layer A does notinclude the composition previously described in this disclosure. Thesealing composition of Layer A has an internal cohesive strength greaterthan the internal cohesive strength of the composition of Layer B.

The sealing composition of Layer A may have an internal cohesionstrength that is greater than the internal cohesion strength of thecomposition of Layer B. During initial opening of the reclose film 200,such as when opening a resealable package made with the reclose film200, the initial opening force causes the sealing composition of Layer Ato fail in a direction generally perpendicular to the reclose film 200.Failure of the sealing composition of Layer A may enable the compositionof Layer B to cohesively fail in a direction generally parallel to thereclose film 200 to activate the reclose functionality. Therefore, theinternal cohesion strength of Layer A may be low enough so that themagnitude of the opening force needed to initially open the reclose film200 and activate the reclose and reopen functionality is not excessive.

Referring to FIG. 4, Layer B includes the top facial surface 222 and abottom facial surface 224. The top facial surface 222 of Layer B may bein adhering contact with the bottom facial surface 214 of Layer A.Additionally, the bottom facial surface 224 of Layer B may be inadhering contact with a top facial surface 232 of Layer C. Thus, Layer Bis positioned adjacent to Layer A and in adhering contact with Layer B,and Layer B is disposed between Layer A and Layer C. Layer B comprisesthe compositions previously described in this disclosure that includethe ethylene/α-olefin random copolymer, styrenic block copolymer,tackifier, and oil.

Layer C includes the top facial surface 232 and a bottom facial surface234. As previously discussed, the top facial surface 232 of Layer C maybe in adhering contact with the bottom facial surface 224 of Layer B. Insome embodiments, the bottom facial surface 234 of Layer C may comprisethe film bottom facial surface 204 of the reclose film 200, such as whenthe reclose film 200 includes three layers. Alternatively, in otherembodiments, the bottom facial surface 234 of Layer C may be in adheringcontact with a top facial surface of a subsequent layer. For example,referring to FIG. 5, the bottom facial surface 234 of Layer C may be inadhering contact with a top facial surface 242 of Layer D.

In some embodiments, Layer C may be a structural layer that may providestrength and stiffness to the reclose film 200. In some embodiments,Layer C may include a polymer or copolymer comprising at least anethylene monomer, such as, but not limited to high density polyethylene(HDPE), medium density polyethylene (MDPE), low density polyethylene(LDPE), linear low density polyethylene (LLDPE), very low densitypolyethylene (VLDPE), or combinations of these. For example, in someembodiments, Layer C may include LLDPE. In other embodiments, Layer Cmay include other polymer film materials, such as nylon, polypropylene,polyesters such as polyethylene terephthalate (PET) for example,polyvinyl chloride, other thermoplastic polymers, or combinations ofthese. In some embodiments, Layer C may include additional structuralmaterials, such as nylon for example. In other embodiments, Layer C maybe a sealant layer that includes any of the sealant compositionspreviously discussed in relation to Layer A.

In some embodiments, the reclose film 200 may be a flexible film, whichmay enable the reclose film 200 to conform its shape to seal to varioussubstrates and substrate surfaces.

Additional supplemental layers may be added to the bottom facial surface234 of Layer C to impart any of a number of properties to the multilayerfilm. For Example, referring to FIG. 5, a reclose film 300 that includesfour layers is schematically depicted. As shown, reclose film 300 mayinclude Layer A, Layer B, Layer C, and Layer D. Layer A may again be thesealing layer, and Layer B may be the reclose layer in adhering contactwith the sealing layer (Layer A). The reclose film 300 depicted in FIG.5 includes at least two supplemental layers; Layer C and Layer D. LayerC may have the top facial surface 232 in adhering contact with thebottom facial surface 224 of Layer B. The bottom facial surface 234 ofLayer C may be in adhering contact with the top facial surface 242 ofLayer D. In some embodiments, the bottom facial surface 244 of Layer Dmay be the film bottom facial surface 204 of the reclose film 300.Alternatively, in other embodiments, the bottom facial surface 244 ofLayer D may be in adhering contact with the top facial surface ofanother supplemental layer.

Each of the supplemental layers, such as Layers C and D and othersupplemental layers, may include different materials or combinations ofmaterials that provide different properties to the reclose film 300,such as structural support, insulating properties, moisture resistance,chemical resistance, tear or puncture resistance, optical properties,sealing capability, gas permeability or impermeability properties,friction resistance, other properties, or combinations of these. Forexample, in some embodiments, Layer C may include materials that providestructural support to the multilayer film, and Layer D may include asealing composition, such as the sealing compositions previouslydescribed for Layer A, to enable sealing of the film bottom facialsurface 204 of the reclose film 300 to a second substrate. Layers C andD, as well as other supplemental layers included to the bottom portionof the reclose film 300 may provide a plurality of other functionalitiesto the reclose film 300.

Referring to FIGS. 4 and 5, each of the plurality of layers, such asLayer A, Layer B, Layer C, and any additional supplemental layers, maybe coextruded to form the reclose films 200, 300. For example, in someembodiments, the reclose films 200, 300 may be produced using a blownfilm process. Alternatively, in other embodiments, the reclose films200, 300 may be produced using cast film processes. Other conventionalprocesses for producing multilayer films may also be employed to producethe reclose films 200, 300.

Referring to FIGS. 6A-6D, operation of the reclose film 200 will bedescribed. The reclose film 200 may be initially sealed to a surface 252of a substrate 250. The substrate 250 may be a rigid substrate, such asa rigid container made from plastic, metal, glass, ceramic, coated oruncoated cardboard (e.g., fiberboard, paperboard or other rigidstructure made from wood pulp), other rigid material, or combinations ofthese. Alternatively, the substrate 250 may be a non-rigid or flexiblesubstrate, such as a polymer film, metal foil, paper, natural orsynthetic fabric, other flexible substrate, or combinations of these.For example, in some embodiments, the substrate 250 may include anothermultilayer polymer film. Is some embodiments, the substrate 250 may bethe reclose film 200 itself, such as by folding the reclose film 200 andsealing the reclose film 200 to itself or by providing two separatesheets or webs of the reclose film 200.

Referring to FIG. 5A, the reclose film 200 may be sealed to the surface252 of the substrate 250 by contacting the top facial surface 212 ofLayer A with a surface 252 of the substrate 250 and applying heat,pressure, or a combination of heat and pressure to the reclose film 200to seal the Layer A, which is the sealing layer of the reclose film 200,to the surface 252 of the substrate 250. In some embodiments, Layer A ofthe reclose film 200 may be heat sealed to the substrate 250. Heatsealing may be accomplished by conventional heat sealing processes whichmay be operated at heat sealing temperatures of greater than about 130°C. For example, in some embodiments, Layer A of the reclose film 200 maybe heat sealed to the surface 252 of the substrate 250 at a heat sealingtemperature of from 100° C. to 180° C. In some embodiments, the heatsealing temperature may be from 100° C. to 160° C., from 100° C. to 150°C., from 120° C. to 180° C., from 120° C. to 160° C., from 120° C. to150° C., from 130° C. to 180° C., from 130° C. to 160° C., or from 130°C. to 150° C.

In some embodiments, only a portion of Layer A of the reclose film 200is sealed to the surface 252 of the substrate 250 to form a sealedregion 254. The portions of the reclose film 200 in which Layer A is notsealed to the surface 252 of the substrate 250 may define an unsealedregion 256 of the reclose film 200. In the unsealed region 256, Layer Aof the reclose film 200 is not sealed to the surface 52 of the substrate250 and may be free to move in a direction normal to the surface 252 ofthe substrate 250 so that Layer A of the reclose film 200 is spacedapart from the substrate 250 in the unsealed region 256. For example, insome embodiments, in the unsealed region 256, the reclose film 200 maybe spaced apart from the substrate 250 to define a volume between thereclose film 200 and the substrate 250. Alternatively or additionally,in some embodiments, the unsealed region 256 may provide a tab 258 thatmay enable a force to be exerted on the reclose film 200 relative to thesubstrate 250.

In some embodiments, the sealed regions 254 may exhibit a seal integritysufficient to prevent passage of particulates between the multilayerfilm 200 and the substrate 250 in the sealed region 254. In otherembodiments, seal integrity of the sealed regions 254 may be sufficientto prevent passage of liquids between the multilayer film 200 and thesubstrate 250 in the sealed region 254. In still other embodiments, sealintegrity of the sealed regions 254 may be sufficient to prevent passageof moisture between the multilayer film 200 and the substrate 250 in thesealed region 254. In still other embodiments, seal integrity of thesealed regions 254 may be sufficient to prevent passage of are betweenthe multilayer film 200 and the substrate 250 in the sealed region 254.

Upon sealing the film top facial surface 202 of the reclose film 200 tothe surface 252 of the substrate 250 to form the sealed region 254, abond strength between the bottom facial surface 214 of Layer A and thetop facial surface 222 of Layer B may be greater than a cohesivestrength of the adhesive composition of Layer B. Additionally, aftersealing, a bond strength between the bottom facial surface 224 of LayerB and the top facial surface 232 of Layer C may be also be greater thanan internal cohesion strength of the adhesive composition of Layer B.After sealing, the bond strength of the top facial surface 212 of LayerA to the surface 252 of the substrate 250 may be greater than aninternal cohesion strength of the composition of Layer B. Therefore, thesealing composition of Layer A does not provide reclose functionality tothe reclose film 200. Once sealed to the substrate 250, the reclose film200 does not exhibit reclose functionality until after an initialopening force is applied to the reclose film 200 to separate a portionof the reclose film 200 from the substrate 250.

Referring to FIG. 6B, the reclose functionality of the reclose film 200may be activated by applying an initial opening force F1 on the reclosefilm 200. The initial opening force F1 may be applied in a directiongenerally perpendicular to the film top facial surface 202 of thereclose film 200. The initial opening force F1 may be greater than athreshold force, at which separation of the reclose film 200 occurs toactivate the reclose functionality. The initial opening force F1 may besufficient to cause Layer A to fail at an interface 260 between thesealed region 254 and the unsealed region 256 of the reclose film 200.In some embodiments, the initial opening force F1 for the reclose film200 may be less than or equal to about 40 newtons/inch (N/in), less thanless than or equal to 37 N/inch, less than or equal to 35 N/inch, oreven less than or equal to 30 N/inch after being heat sealed at a heatsealing temperature of 150° C. The initial opening force F1 may bedetermined according to the Peel Adhesion Test as described herein. Theinitial opening force F1 of the multilayer film may be determinedaccording to the test method for peel strength described herein at theheat sealing temperature of 130° C. In some embodiments, the initialopening force F1 for the reclose film 200 may be from 25 N/inch to 40N/inch, from 25 N/inch to 37 N/inch, from 25 N/inch to 35 N/inch, from27 N/inch to 40 N/inch, from 27 N/inch to 37 N/inch, from 27 N/inch to35 N/inch, from 30 N/inch to 40 N/inch, from 30 N/inch to 37 N/inch, orfrom 30 N/inch to 35 N/inch after the multilayer film is heat sealed ata heat sealing temperature of 130° C.

At an initial opening force F1 greater than the threshold force, Layer Aruptures at an interface 260 of the sealed region 254 and the unsealedregion 256. Layer A may rupture in a direction from the bottom facialsurface 214 to the top facial surface 212 of Layer A (e.g., generallyperpendicular to the film top facial surface 202 or in the +/−Zdirection of the coordinate axis of FIG. 5B). The internal cohesionstrength of the composition of Layer B is less than the initial openingforce and less than the bond strengths between the top facial surface222 of Layer B and the bottom facial surface 214 of Layer A, and betweenthe bottom facial surface 224 of Layer B and the top facial surface 232of Layer C. Thus, once Layer A ruptures at the interface 260 of thesealed region 254 and the unsealed region 256, Layer B in the sealedregion 254 cohesively fails in a direction generally parallel to thefilm top facial surface 202. Cohesive failure of Layer A results in afirst portion 262 of the composition of Layer B coupled to the bottomfacial surface 214 of Layer A and a second portion 264 of thecomposition of Layer B coupled to the top facial surface 232 of Layer C.Thus, in the opened portion of the sealed region 254, the composition ofLayer B covers both the top facial surface 232 of Layer C and the bottomfacial surface 214 of Layer A. The portion of Layer A in the sealedregion 254, including the opened portion of the sealed region 254,remains sealed to the substrate 250 (i.e., the top facial surface 212 ofLayer A remains sealed to the surface 252 of the substrate 250 in thesealed region 254, including the opened portion).

Referring to FIG. 7A, a cross-section of the reclose film 200 andsubstrate 250 of FIG. 6A is taken along reference line 7A-7A. In theembodiments schematically represented in FIG. 6A, the sealed region 254may bounded by the unsealed region 256 on one side of the sealed region254 and a second unsealed region 257 on the other side of the sealedregion. During initial opening, the initial opening force F1 may causeLayer A to rupture at the interface 260 of the sealed region 254 and theunsealed region 256 in a direction generally perpendicular to the filmtop facial surface 202, as previously described in relation to FIG. 6B.As shown in FIG. 7B, the opening force F1 may cause Layer B tocohesively fail in a direction generally parallel to the film top facialsurface 202, as previously described. When cohesive failure of Layer Breaches a second interface 261 between the sealed region 254 and thesecond unsealed region 257, the initial opening force F1 may cause LayerA to rupture again at the second interface 261 between the sealed region254 and the second unsealed region 257. At the second interface 261,Layer A may rupture in a direction generally perpendicular to the filmtop facial surface 202. After initial opening of the reclose film 200, aportion of Layer A corresponding to the sealed region 254 is separatedfrom the reclose film 200 and remains coupled to the substrate 250.

Initial opening of the reclose film 200 activates the reclosefunctionality of the multilayer film resulting in the first portion 262of the composition of Layer B on the bottom facial surface 214 of LayerA and the second portion 264 of the composition of Layer B on the topfacial surface 232 of Layer C. Referring to FIG. 6C, to reclose thesealed region 254 of the reclose film 200, the first portion 262 of thecomposition of Layer B may be returned into contact with the secondportion 264 of the composition of Layer B and a reclose pressure F2 maybe applied to the reclose film 200 in the sealed region 254. The reclosepressure F2 may be applied to the reclose film 200 in a directiongenerally perpendicular to the film bottom facial surface 204. Thereclose pressure F2 may be sufficient to cause the first portion 262 andthe second portion 264 of the composition of Layer B to re-adhere toreform Layer B. In some embodiments, the reclose pressure F2 may be lessthan or equal to 40 N/inch, less than or equal to 30 N/inch, less thanor equal to 20 N/inch, or even less than or equal to 10 N/inch.

Applying the reclose pressure F2 to the multilayer film causes the firstportion 262 and the second portion 264 of the composition of Layer B tore-adhere. Re-adherence of the first portion 262 and the second portion264 of the composition to form a contiguous Layer B, may reseal thesealed region 254 of the multilayer film.

Referring to FIG. 6D, after reclosing the reclose film 200, the reclosefilm 200 may be reopened by applying a reopen force F3 to the reclosefilm 200. Reopen force F3 may be applied to the multilayer film in adirection generally perpendicular to the film top facial surface 202.The reopen force F3 may be applied by gripping the reclose film 200 inthe unsealed region 256 and pulling the reclose film 200 away from thesubstrate 250. Application of the reopen force F3 may cause thecomposition of Layer B to cohesively fail in a direction parallel to thefilm top facial surface 102. Again, cohesive failure of the compositionof Layer B results in a first portion of the composition coupled to thebottom facial surface 214 of Layer A and a second portion of thecomposition coupled to the top facial surface 232 of Layer C.

The reopen force F3 may be sufficient to cause the composition of LayerB to cohesively fail. In some embodiments reopen force F3 may be greaterthan or equal to 1 N/inch, greater than or equal to 1.5 N/inch, greaterthan or equal to 2.0 N/inch, greater than or equal to 2.5 N/inch, oreven greater than or equal to 3 N/inch for the reclose film 200 heatsealed to the substrate 250 at a heat seal temperature of 130° C. Thereopen force F3 may be determined according to the Peel Adhesion Testdescribed herein. The reclose film 200 may be subjected to multiplecycles of reopening and reclosing. After multiple reopen/reclose cycles,the reclose film 200 may exhibit a reopen force F3 of greater than orequal to 1.5 N/inch, greater than or equal to 2.0 N/inch, greater thanor equal to 2.5 N/inch, or even greater than 3.0 N/inch. For example, insome embodiments, the reclose film 200, which is initially heat sealedto the substrate 250 at a heat seal temperature of 130° C., may exhibita reopen force F3 after at least four reopen/reclose cycles of greaterthan 2.0 N/inch. In some embodiments, the reclose film 200 may exhibit areopen force of from 2.0 N/inch to 10.0 N/inch, from 2.0 N/inch to 7.0N/inch, from 2.0 N/inch to 5.0 N/inch, from 2.5 N/inch to 10.0 N/inch,from 2.5 N/inch to 7.0 N/inch, or from 2.5 N/inch to 5.0 N/inch afterbeing heat sealed at a heat seal temperature of 130° C., initiallyopened, and after experiencing at least 4 reclose-reopen cycles.

Referring back to FIGS. 3A-4, in one or more embodiments, the rear wall120 of a reclosable package 100 comprises a reclose film. In suchembodiments, the interior surface of the rear wall 120 may comprise thetop facial surface 212 of Layer A. Further, the exterior surface of therear wall 120 may comprise a bottom facial surface 234 of Layer C. LayerB is disposed between Layer A and Layer C with a top facial surface 214of Layer B in adhering contact with a bottom facial surface of Layer A222 and a top facial surface 224 of Layer C is in adhering contact withthe bottom facial surface 232 of Layer B. In such embodiments, the topfacial surface 212 of Layer A may be sealed to the exterior surface ofthe front wall 110. In one or more embodiments, the application of anopening force to the rear wall 120 in a direction away from the frontwall 110 is operable to cause the cohesive failure of Layer B,separating a portion of the rear wall 120 from the front wall 110. Inone or more embodiments, after the cohesive failure of Layer B, at leastpart of Layer B is disposed on the front wall 110 and at least part ofLayer B is disposed on the rear wall 120.

In one or more embodiments, the front wall 110 and the rear wall 120 ofthe reclosable package 100 comprise a reclose film. In such embodiments,the exterior surface of the front wall 110 may comprise the top facialsurface 212 of Layer A₁. Further, the interior surface of the front wall110 may comprise a bottom facial surface 234 of Layer C₁. Layer B₁ isdisposed between Layer A₁ and Layer C₁ with a top facial surface 214 ofLayer B₁ in adhering contact with a bottom facial surface 222 of LayerA₁ and a top facial surface 224 of Layer C₁ is in adhering contact withthe bottom facial surface 232 of Layer B₁. In one or more embodiments,the front wall 110 of the reclosable package 100 comprises a reclosefilm. In such embodiments, the exterior surface of the front wall 110may comprise the top facial surface 212 of Layer A₂. Further, theinterior surface of the front wall 110 may comprise a bottom facialsurface 234 of Layer C₂. Layer B₂ is disposed between Layer A₂ and LayerC₂ with a top facial surface 214 of Layer B₂ in adhering contact with abottom facial surface 222 of Layer A₂ and a top facial surface 224 ofLayer C₂ is in adhering contact with the bottom facial surface 232 ofLayer B₂. In one or more embodiments, Layer A₁ may be in adheringcontact with Layer A₂. In one or more embodiments, the application of anopening force proximate to the closure region 150 is operable to causethe cohesive failure of either Layer B₁ or Layer B₂, separating aportion of the rear wall 120 from the front wall 110.

In one or more embodiments, the closure region 150 comprises a reclosefilm disposed between the rear wall 120 and the front wall 110. In suchembodiments, both the Layer A and the Layer C may be sealant layers. Atop facial surface 212 of the Layer A may be in adhering contact withthe interior surface of the rear wall 120 and a bottom facial surface234 of Layer C may be in adhering contact with the exterior surface 112of the front wall 110. Layer B is disposed between Layer A and Layer Cwith a top facial surface 214 of Layer B in adhering contact with abottom facial surface 222 of Layer A and a top facial surface 224 ofLayer C is in adhering contact with the bottom facial surface 232 ofLayer B. In one or more embodiments, the application of an opening forceproximate to the closure region 150 is operable to cause the cohesivefailure of either Layer B₁ or Layer B₂, separating a portion of the rearwall 120 from the front wall 110.

In one or more embodiments where the front wall 110, the rear wall 120,or both comprises a reclose film, seal regions 160 may be formed by theselective application of heat, pressure, or both to areas of the closureregion 150. For example, applying heat, pressure, or both to an area orareas of the closure region 150 may result in a seal region 160 beingformed in the area or areas. Conversely, an unsealed region 170 orregions may develop in areas of the closure region 150 where heat orpressure were not applied. In one or more embodiments, heat, pressure,or both may be applied in a repeating geometric pattern within theclosure region 150 to form a repeating geometric pattern of seal regions160.

In one or more embodiments, the application of an opening force, eitheran initial opening force or a reopen force, proximate to the closureregion 150 is operable to separate at least part of the front wall 110from the rear wall 120, breaking the continuous seal between the frontwall 110 and the rear wall 120 across a width w₁ of the reclosablepackage 100. Referring again to FIG. 3B, after an opening force isapplied proximate to the closure region 150, at least part of the frontwall 110 is separated from the rear wall 120. In one or moreembodiments, as shown in FIG. 3B, the front wall 110 and rear wall 120may be separated across the entire width w, however, the front wall 110and rear wall 120 are still sealed together throughout the border seal138. In one or more embodiments, after separating at least part of thefront wall 110 from the rear wall 120, contacting the front wall 110 tothe rear wall 120 proximate to the closure region 150 and applying aclosing pressure proximate to the closure region 150 is operable toreform the seal between the front wall 110 to the rear wall 120 acrossthe width w₂ of the closure region 150.

The magnitude of the opening force required to separate at least part ofthe front wall from the rear wall is largely dependent on the sealgeometry of the closure region 150. By altering the arrangement, size,shape, and distribution of seal regions 160 and unsealed regions 170within the closure region 150, the magnitude of the opening forcerequired can be tuned. Similarly, the magnitude of the closing pressurerequired to reform the seal between the front wall 110 and rear wall 120across a width w₁, w₂ is also largely dependent on the seal geometry ofthe closure region 150. By altering the arrangement, size, shape, anddistribution of seal regions 160 and unsealed regions 170 within theclosure region 150, the magnitude of the closing pressure required canbe tuned.

In one or more embodiments, the closure region 150 comprises a repeatinggeometric pattern of seal regions as shown in FIGS. 1A-1C. In one ormore embodiments, the repeating geometric patterns may include, but arenot limited to, triangles, quadralaterals, trapezoids, parallelagrams,rhombi, pentagons, hexagons, tessellating polygons, other polygons,circles, ovoids, ellipses, spirals, shapes comprising right angles, orcombinations thereof. In other embodiments, any imprint, emboss, design,trademark, emblem, or icon may be incorporated into the closure region150 and defined by a plurality of seal regions 160, unsealed regions170, or both. It should be understood, that by making modifications tothe seal bar, a machining component that applies heat, pressure, or bothto the closure region 150, and pattern or design of seal regions 160 orunsealed regions 170 may be incorporated into the closure region 150.

In one or more embodiments, the area fraction of seal regions 160,X_(S), is defined as the total combined area of all seal regions 160divided by the total area of the closure region 150. In otherembodiments, the area fraction of unsealed regions 170, X_(U), isdefined as the total combined area of all unsealed regions 170 dividedby the total are of the closure region 150. In one or more embodiments,the seal fraction, as defined as the ratio of the X_(S) to the X_(U).The seal fraction is always a positive number and as the seal fractionincreases so does the initial opening force required to break thecontinuous seal.

In one or more embodiments, the walls of the reclosable package comprisea flexible film. In some embodiments, the film may be formed by anyconventional means known in the art including, but not limited to, blownfilm extrusion, cast film extrusion, or other extrusion techniques knownin the art. In one or more embodiments, the forming of the film furtherutilizes coextrusion, a process in which multiple layers of material maybe extruded simultaneously. In one or more coextrusion applications,multiple layers of different types of material may be extrudedsimultaneously. Techniques of coextrusion may be applied to anyconventional methods known in the art including, but not limited toblown film extrusion or cast film extrusion. In one or more embodiments,after the film is formed, but before it is incorporated into a package,the film may be laminated. In other embodiments, the film is notlaminated prior to the formation of the package.

FIGS. 2A-3B illustrate only a few examples of reclosable package designsthat can incorporate the reclosable film and compositions according toembodiments of the present disclosure. A person of ordinary skill in theart can readily identify other package types, shapes, and sizes in whichthe reclosable film and composition disclosed herein may beincorporated. For example, the reclosable film and/or compositions maybe incorporated into package shapes and sizes for which zippers or othermechanical means have been used to provide reclosability to the package.Additionally, the reclosable films and compositions may be incorporatedinto a broad range of package types and shapes that include at least oneflexible film. Examples of these packaging types may include, but arenot limited to tray packaging; pouch packaging such as pillow pouches,vertical form fill and seal (VFFS) packaging, horizontal form fill andseal packages, stand-up pouches, or other pouches; bags; boxes; or othertype of packaging. The reclosable films and compositions may beincorporated into primary packaging or secondary packaging, such asoverwraps, bags, or other secondary packaging. Other packaging types,shapes and sizes having the reclosable film and/or compositionsdisclosed herein are also contemplated.

In some embodiments, the reclosable packaging disclosed herein may beused to package food products, beverages, consumer goods, personal careitems, or other articles. Food products that may be packaged using thereclosable packaging disclosed herein may include particular foodproducts, such as sugar, spices, flour, coffee, or other particulates;solid food products; such as meats, cheeses, snacks, vegetables, bakedgoods, pet food, pasta, or other solid food products; liquid foodproducts, such as but not limited to milk, soup, beverages, or otherliquid food products; and/or bulk food items such as but not limited torice, dog food, flour or other grains, or other bulk food items.Consumer goods that may be packaged using the reclosable packaging mayinclude but are not limited to consumer electronics, hardware, toys,sporting goods, plastic utensils, autoparts, batteries, cleaningsupplies, software packages, salt, or other consumer goods. Thereclosable packages disclosed herein may also be incorporated intopost-consumer storage bags, such as food storage bags or freezer bags. Aperson of ordinary skill in the art can recognize many other potentialuses for the reclosable packaging disclosed herein.

EXAMPLES

The following Examples illustrate various embodiments of the compositionand multilayer film described herein. The compositions of the followingexamples and comparative examples were compounded using a single stagetwin-screw extrusion process. The compounding operation is performed ona Century-ZSK-40 45.375 length-to-diameter ratio (L/D) (Eleven Barrels)extruder using one screw design with one oil injector, in barrel 4. Theextruder has a maximum screw speed of 1200 rpm. The polymers and thePICCOTAC tackifier were fed into the main feed throat of the extruder.The HYDROBRITE 550 process oil is added through an injection port atbarrel 4. The compound is pelletized using an underwater Gala system,which is equipped with a 12 hole (2.362 mm hole diameter) Gala die with6 holes plugged, and a 4 blade hub cutter. Soap and antifoam were addedto the water bath as needed to prevent clumping. The pellets werecollected and dusted with 2000 ppm POLYWAX 2000 (available from BakerHughes), and then dried under nitrogen purge for 24 hours. Screw speedis set at 180 RPM for all the samples. Temperature profile is set asfollows: 100° C. (zone 1), 100° C. (zone 2), 180° C. (zone 3), 180° C.(zone 4), 160° C. (zone 5), 160° C. (zone 6), 110° C. (zone 7), 110° C.(zone 8), 90° C. (zone 9), 90° C. (zone 10), and 90° C. (zone 11), witha die temperature of 140° C.

Table 1 below includes properties of commercial polymers used in theExamples that follow.

TABLE 1 Properties of commercial polymers Melt Index Density Material(I₂) g/10 min (g/cc) Supplier INFUSE ™ 9107 1.00 0.866 The Dow Chemical(olefin block copolymer) Company, Midland, MI DOW ™ LDPE 5004i 4.200.924 The Dow Chemical (LDPE) Company, Midland, MI DOWLEX ™ NG 1.000.935 The Dow Chemical 2038.68G (LLDPE) Company, Midland, MI ENGAGE ™8842 1.00 0.857 The Dow Chemical (polyolefin plastomer) Company,Midland, MI VECTOR ® 4113A 9.20 0.920 Dexco Polymers, (styrene-isopreneHouston, TX triblock copolymer) VECTOR ® 4213A 12.0 0.940 DexcoPolymers, (SIS triblock/SI Houston, TX diblock copolymer) ELVAX ® 31247.0 0.930 E. I. du Pont de (ethylene-vinyl Nemours and acetate copolymerCompany, Inc. w/9 wt. % vinyl acetate)

Example 1: Example Composition

A composition according to the present disclosure was made by combining43.4 wt. % ethylene/α-olefin random copolymer, 20 wt. % styrenic blockcopolymer, 30 wt. % tackifier, and 6.6 wt. % mineral oil. Theethylene/α-olefin random copolymer was ENGAGE™ 8842. The styrenic blockcopolymer was VECTOR 4113A styrene-isoprene triblock copolymer, whichhad a styrene content of 18 wt. %, and a diblock content of 42 wt. %.The tackifier was PICCOTAC 1100 C₅ tackifier available from EastmanChemical Company. The tackifier has a ring and ball softening point of100° C. and a Mw of 2900. The mineral oil was HYDROBRITE 550 mineral oilavailable from Sonneborn and exhibited a density of 0.87 g/cm³ andparaffinic carbon content of about 70 wt. %.

The individual constituents of the composition of Example 1 werecompounded according to the previously described single stage twin-screwextrusion process. The composition of Example 1 was then tested fordensity, melt index (I₂) at a temperature of 190° C. and a load of 2.16kg, and melt flow rate at a temperature of 230° C. and a load of 2.16kg. The results for the density, melt index (I₂), and melt flow rate forthe composition of Example 1 are provided below in Table 2.

Comparative Example 2: Comparative Adhesive Composition Formulated withOlefin Block Copolymer

In Comparative Example 2, a comparative adhesive composition wasproduced using an olefin block copolymer in place of theethylene/α-olefin random copolymer of Example 1. The composition ofComparative Example 2 included 43.4 wt. % olefin block copolymer, 20 wt.% of the styrenic block copolymer, 30 wt. % tackifier, and 6.6 wt. %mineral oil. The olefin block copolymer was INFUSE™. The styrenic blockcopolymer, tackifier, and mineral oil in Comparative Example 2 were thesame as described above for Example 1.

The individual constituents of Comparative Example 2 were compoundedusing the previously described single stage twin-screw extrusionprocess. The composition of Comparative Example 2 was tested fordensity, melt index (I₂) at a temperature of 190° C. and a load of 2.16kg, and melt flow rate at a temperature of 230° C. and a load of 2.16kg. The results for the density, melt index (I₂), and melt flow rate forthe composition of Comparative Example 2 are provided below in Table 2.

Comparative Example 3: Comparative Adhesive Composition Formulated witha Lesser Amount of Olefin Block Copolymer

In Comparative Example 3, a comparative adhesive composition wasproduced using an olefin block copolymer in place of theethylene/α-olefin random copolymer of Example 1. The composition ofComparative Example 3 included less olefin block copolymer and morestyrenic block copolymer compared to the composition of ComparativeExample 2. Comparative Example 3 was prepared to investigate the effectof increasing the amount of the styrenic block copolymer in the adhesivecomposition.

The composition of Comparative Example 3 included 33.4 wt. % olefinblock copolymer, 30 wt. % of the styrenic block copolymer, 30 wt. %tackifier, and 6.6 wt. % mineral oil. The olefin block copolymer wasINFUSE™ 9107. The styrenic block copolymer, tackifier, and mineral oilwere the same as described above for Example 1.

The individual constituents of Comparative Example 3 were compoundedusing the previously described single stage twin-screw extrusionprocess. The composition of Comparative Example 3 was tested fordensity, melt index (I₂) at a temperature of 190° C. and a load of 2.16kg, and melt flow rate at a temperature of 230° C. and a load of 2.16kg. The results for the density, melt index (I₂), and melt flow rate forthe composition of Comparative Example 3 are provided below in Table 2.

Comparative Example 4: Commercially Available Adhesive Composition forReclose Multilayer Films

For Comparative Example 4, a commercially available pressure sensitiveadhesive composition marketed as providing reclose capability tomultilayer film compositions was obtained. The commercially availablecomposition comprised a styrene-isoprene-styrene block copolymer,hydrocarbon tackifier, and talc. The commercially available compositiondid not include a polyethylene component, such as apolyethylene/α-olefin copolymer. The commercially available adhesivecomposition was tested for density, melt index (I₂) at a temperature of190° C. and a load of 2.16 kg, and melt flow rate at a temperature of230° C. and a load of 2.16 kg. The results for the density, melt index(I₂), and melt flow rate for the composition of Comparative Example 4are provided below in Table 2.

Comparative Example 5: Comparative Adhesive Composition Formulated withStyrenic Block Copolymer, Tackifier, and Oil

In Comparative Example 5, a comparative adhesive composition wasproduced using a styrenic block copolymer without the ethylene/α-olefinrandom copolymer of Example 1. The composition of Comparative Example 5included 64.3 wt. % styrenic block copolymer, 30 wt. % tackifier, and6.6 wt. % mineral oil. The styrenic block copolymer was VECTOR® 4213ASIS triblock/SI diblock copolymer. The tackifier and mineral oil werethe same as described above for Example 1.

The individual constituents of Comparative Example 5 were compoundedusing the previously described single stage twin-screw extrusionprocess. The composition of Comparative Example 5 was tested fordensity, melt index (I₂) at a temperature of 190° C. and a load of 2.16kg, and melt flow rate at a temperature of 230° C. and a load of 2.16kg. The results for the density, melt index (I₂), and melt flow rate forthe composition of Comparative Example 5 are provided below in Table 2.

Comparative Example 6. Comparative Adhesive Composition Formulated withEVA and Styrenic Block Copolymer

In Comparative Example 6, a comparative adhesive composition wasproduced using an ethylene-vinyl acetate copolymer (EVA) in place of theethylene/α-olefin random copolymer of Example 1. The composition ofComparative Example 6 included 20.0 wt. % EVA, 43.4 wt. % styrenic blockcopolymer, 30 wt. % tackifier, and 6.6 wt. % mineral oil. The EVA wasELVAX® ethylene-vinyl acetate copolymer having 9 wt. % vinyl acetate.The styrenic block copolymer, tackifier, and mineral oil were the sameas described above for Example 1.

The individual constituents of Comparative Example 6 were compoundedusing the previously described single stage twin-screw extrusionprocess. The composition of Comparative Example 6 was tested fordensity, melt index (I₂) at a temperature of 190° C. and a load of 2.16kg, and melt flow rate at a temperature of 230° C. and a load of 2.16kg. The results for the density, melt index (I₂), and melt flow rate forthe composition of Comparative Example 6 are provided below in Table 2.

Example 7: Comparison of Properties of the Compositions of Example 1 andComparative Examples 2-6

Table 2, which is provided below, includes the density, melt index (I₂),and melt flow rate for the composition of Example 1 and the adhesivecompositions of Comparative Examples 2-6.

TABLE 2 Properties of the composition of Example 1 compared to theproperties of the adhesive compositions of Comparative Examples 2-4 MFRDensity Melt Index (I2) (230° C./ Example (g/cm³) (g/10 min) 2.16 kg)Ex. 1 0.904 10.0 32.5 Comp. Ex. 2 0.907 8.6 26.3 Comp. Ex. 3 0.913 13.853.7 Comp. Ex. 4 >0.920 56.5 N/A Comp. Ex. 5 0.942 20.4 127.6 Comp. Ex.6 0.933 44.1 151.1

The composition of Example 1 and the adhesive compositions ofComparative Examples 2, 3, 5, and 6 were additionally tested using DSCto determine the melting curves of the compositions, from which thecrystallization temperatures (Tc ° C.), melt temperature (Tm ° C.),glass transition temperature (Tg ° C.), heat of crystallization (ΔHcjoules/gram (J/g)), and heat of melting (ΔHm J/g) for each composition,in accordance with the testing procedure previously described herein.These properties are provided below in Table 3. The composition ofExample 1 and the adhesive compositions of Comparative Examples 2, 3, 5,and 6 were additionally testing using DMS to determine the dynamic meltviscosity (η*millipascal seconds (mPa-s)) at 150° C., the ratio of thedynamic melt viscosity at 0.1 radians per second to the dynamic meltviscosity at 100 radians per second at a temperature of 150° C. (η*ratioat 150° C.), and the storage modulus (G′ @ 25° C. dyne/cm²) for eachcomposition, according to the DMS testing procedure previously describedherein. The results of the DMS testing are provided below in Table 3.The composition of Example 1 was tested two times, and the resultsreported in Table 3 below as Ex. 1-A and 1-B.

TABLE 3 Melt temperature, crystallization temperature, dynamic meltviscosity, and storage modulus data for the compositions of Example 1and Comparative Examples 2-6 Ex. 1-A Ex. 1-B Comp. 2 Comp. 3 Comp. 5Comp. 6 T_(c1) (° C.) 16.5 17.2 101.6 101.5 — 78.8 T_(c2) (° C.) — — — —— 52.1 ΔH_(c) (J/g) 16.3 14.9  22.0  19.5 — 17.0 T_(g) (° C.) −54.55−53.7  −52.2 −53.1 −54.7 −52.0  T_(m1) (° C.) 42.2 43.2 119.3 119.0 —93.0 ΔH_(m) (J/g) 16.9 18.1  18.6  16.4 — — η* (mPa-s) 4.0 × 10⁶ 3.3 ×10⁶ 3.3 × 10⁶ 3.1 × 10⁶ 7.9 × 10⁶ 2.0 × 10⁶ 150° C. η* ratio at  8.9 7.7  17.5  17.0  64.9 11.8 150° C.

As shown in Table 3 above, the composition of Examples 1-A and 1-Bexhibited a lower crystallization temperature and melt temperatureprofile compared to the adhesive compositions of Comparative Examples 2,3, 5, and 6. Without being bound by theory, it is believed that lowercrystallization and melting temperatures may reduce or prevent secondarycrystallization of the constituents of the composition, which increasesthe cohesive strength of the composition. Increased cohesive strengthmay provide lower opening force for the composition and more tackiness,which increases the reclose force. Thus, the lower crystallization andmelting temperatures of the composition of Example 1 (Ex. 1-A, 1-B) mayreduce or prevent secondary crystallization of the composition, therebyincreasing the cohesive strength of the composition compared to thecompositions of Comparative Examples 2, 3, 5, and 6. The lowercrystallization and melting temperatures of the composition of Example 1enables the composition of Example 1 to exhibit a greater reclose forcecompared to the compositions of Comparative Examples 2, 3, 5, and 6.

Additionally, the dynamic melt viscosity ratio (η*ratio) at 150° C. forthe composition of Examples 1-A and 1-B were less than the dynamic meltviscosity ratios of Comparative Examples 2, 3, 5, and 6. Without beingbound by theory, it is believed that a lower dynamic melt viscosityratio translates to more consistent behavior in response to differentshear rates, such as the different shear rates experienced by the filmlayer during film fabrication (e.g., blown film extrusion) or sealingconditions. The compositions of Comparative Examples 2, 3, 5, and 6 havegreater dynamic melt viscosity ratios, and therefore it is expected tobe harder to maintain a stable bubble during blown film extrusion ifshear rate changes. Additionally, the adhesive layer made from thecompositions of Comparative Examples 2, 3, 5, and 6 could thin out to agreater extent with increases in sealing pressure, which would reducethe thickness of the adhesive layer and reduce the amount of adhesivecomposition to enable cohesive peeling through the adhesive andpackaging resealing. The composition of Examples 1-A and 1-B, whichexhibited a reduced dynamic melt viscosity ratio of the compared to thecompositions of Comparative Examples 2, 3, 5, and 6, is less sensitiveto changes in shear rates, and therefore, the compositions of Examples1-A and 1-B may be easier to process into the multilayer film andprovide more consistent performance over a range of sealing temperaturesand pressures compared to the compositions of Comparative Examples 2, 3,5, and 6.

Example 8: Multilayer Films with the Compositions of Example 1 andComparative Examples 2-4

In Example 8, each of the composition of Example 1 and adhesivecompositions of Comparative Examples 2 and 3 were used to make amultilayer film to evaluate the reclose properties of the compositions.The multilayer films were five-layer films made using blown filmextrusion and included Layer A, Layer B, Layer C, Layer D, and Layer E.Layer A was a seal layer comprising 98.4 wt. % DOW LDPE 5004i, 1.0 wt. %AMPACET 10063 antiblock masterbatch available from Ampacet Corporation,and 0.6 wt. % AMPACET 10090 slip masterbatch available from AmpacetCorporation. Layer B included the composition of Example 1 or one of theadhesive compositions of Comparative Examples 2-4. Layers C, D, and Eall included identical layers of 100 wt. % DOWLEX 2038.68G LLDPE. Theformulations for each multilayer film of Example 8 are provided below inTable 4.

TABLE 4 Multilayer film formulations for Example 8 Ex. Ex. 8A Comp. 8BComp. 8C Thickness 3 3 3 (mil) Layer A LDPE 5004i LDPE 5004i LDPE 5004iLayer B Ex. 1 Comp. 2 Comp. 3 Layer C DOWLEX DOWLEX DOWLEX 2038.68G2038.68G 2038.68G Layer D DOWLEX DOWLEX DOWLEX 2038.68G 2038.68G2038.68G Layer E DOWLEX DOWLEX DOWLEX 2038.68G 2038.68G 2038.68G Layer10/20/20/20/30 10/20/20/20/30 10/20/20/20/30 ratio (%)

The blown film extrusion samples were fabricated using a LABTECH 5-layerblown film line, and each layer was formed at the same temperature of190° C. The heat seal layer was positioned on the outside of the bubble,and the material was self-wound on uptake rollers. Film fabricationconditions for films 6A-6C are shown in Table 5.

TABLE 5 Blown film fabrication conditions for making the multilayerfilms of Example 8 Film ID 6A 6B 6C Output (kg/hr) 30-35 17.3 17.3 Gauge(micron) 70 76.2 76.2 Layflat (cm) 31.75 33.0 33.0 Line speed (m/min)<1.5 5.0 5.0 Melt temperature (° C.) Extruder 1 215° C. 207 207 Extruder2 190° C. 152 152 Extruder 3 220° C. 218 218 Extruder 4 220° C. 214 214Extruder 5 220° C. 211 211 Melt pressure (megapascals) Extruder 1 <55006 6 Extruder 2 <5500 7 7 Extruder 3 <5500 23 23 Extruder 4 <5500 31 31Extruder 5 <5500 21 21

The multilayer films of Example 8 and shown in Tables 4 and 5 are ofgood integrity. These multilayer films of Example 8 are flexible films,formed from only coextrudable polymer formulations. These multilayerfilms can be used for packaging products, and can be processed onconventional film converting equipment.

A fourth film, comparative film 8D, was obtained and evaluated.Comparative film 8D was a commercially-available multilayer filmbelieved to have been made by a blown film process at conditions typicalin the blown film industry. The film 8D included a pressure sensitiveadhesive layer that was found to include primarily an SIS blockcopolymer. The film 8D was found to not include a polyethylene copolymerof any kind.

Each of the multilayer film 8A, and comparative films 8B, 8C, and 8D ofExample 8 were adhesively laminated to a 48 gauge biaxially orientedpolyethylene terephthalate (PET) (available from DuPont Teijin) usingMORFREE 403A (solventless adhesive) and co-reactant C411 (solvent-lessadhesive) both of which are available from the Dow Chemical Company,Midland Mich., to form a final laminate film structure (sealant/PSA/core(3 layers)/solventless adhesive/PET). The multilayer films of Example 8were tested for initial peel strength and reclose peel strengthaccording to the peel adhesion test previously described herein. Thereclose peel strength for each film was measured at time intervals afterthe initial opening peel strength. The result for the initial peelstrength and subsequent reclose peel strengths for each of film 8A, andcomparative films 8B, 8C, and 8D are provided below in table 6. The peelstrength measurements are in units of newtons per inch (N/in) in Table 6below.

TABLE 6 Initial peel adhesion and reclose peel adhesion for themultilayer films of Example 8 Film Initial ID/Seal Peel Temp Strength (°C.) Layer B (N/in) Reopen Peel Strength (N/in) 20 20 20 20 30 20 60 20Film 6A Ex. 1 Time = 0 min min min min min min min min 130 Ex. 1 34.75.7 3.7 2.9 2.8 2.5 NA 2.3 2.2 150 Ex. 1 40.5 7.7 4.7 3.9 3.1 3.1 NA 2.72.4 20 20 20 20 30 20 60 20 Comp. 6B Comp. 2 Time = 0 min min min minmin min min min 130 Comp. 2 43.8 6.6 4.4 3.7 3.2 2.9 NA 2.5 2.1 150Comp. 2 44.5 6.9 5.5 4.6 4.0 3.3 NA 2.6 2.4 20 20 20 20 20 50 20 20Comp. 6C Comp. 3 Time = 0 min min min min min min min min 130 Comp. 327.7 4.6 3.8 3.3 2.5 2.2 2.4 2.1 1.9 140 Comp. 3 29.0 3.9 2.9 2.0 1.81.8 1.4 1.4 1.3 150 Comp. 3 30.6 3.2 2.0 1.5 1.1 1.0 1.0 0.9 0.8 20 2020 20 20 50 20 20 Comp. 6D Comp. 4 Time = 0 min min min min min min minmin 140 Comp. 4 22.6 0.3 0.2 0.1 0.1 0.1 0.1 0.1 0.1 150 Comp. 4 18.71.2 0.6 0.4 0.1 0.1 0.3 0.1 0.0

As shown in Table 6 above, film 8A, which included the composition ofExample 1, exhibited an initial peel strength 34.7 N/in at a heat sealtemperature of 130° C. After being heat sealed at a temperature of 130°C. and initially opened, film 8A exhibited a reclose peel adhesion of atleast 2.5 N/in through four reclose cycles and a reclose peel adhesionof greater than 2.0 N/in after at least 7 reclose cycles. At a sealingtemperature of 150° C., the initial peel adhesion strength of film 8Awas 40.5 N/in and the reclose peel adhesion strength was greater than 3N/in after four reclose cycles and greater than 2.0 after at least 7reclose cycles.

Comparative film 8D, which was made with the adhesive composition ofComparative Example 4 that included mostly a styrene block copolymer,exhibited an initial peel strength 18.7 N/in at a heat seal temperatureof 150° C. After being heat sealed at a temperature of 150° C. andinitially opened, comparative film 8D exhibited a reclose peel adhesionof less than 1.0 N/in through four reclose cycles and negligible reclosepeel adhesion of less than 0.1 N/in after at least 7 reclose cycles.Thus, at an initial sealing temperature of 150° C., initial peelstrength of 40.5 N/in of the film 8A made with the composition ofExample 1 was substantially higher than the initial peel strength of thecomparative film 8D that included the styrene block copolymer pressuresensitive adhesive (PSA) of Comparative Example 4. Film 8A alsoexhibited a substantially greater reclose peel strength after 4 cyclesand 7 cycles compared to the comparative film 8D that included thestyrene block copolymer PSA of Comparative Example 4.

Comparative film 8B included the adhesive composition of ComparativeExample 2 for Layer B. The adhesive composition of Comparative Example 2included 43.4 wt. % of an ethylene/α-olefin block copolymer and 20 wt. %styrenic block copolymer. The film 8A included the composition ofExample 1, which comprised 43.4 wt. % of the ethylene/α-olefin randomcopolymer. Thus, the difference in composition between the compositionof Example 1 and the adhesive composition of Comparative Example 2 isthe substitution of the ethylene/α-olefin random copolymer in Example 1for the ethylene/α-olefin block copolymer used in Comparative Example 2.At a sealing temperature of 130° C., film 8A, which included thecomposition of Example 1, exhibited an initial peel strength of 34.7N/inch. Comparative film 8B, which included the adhesive composition ofComparative Example 2, exhibited an initial peel strength of 43.8N/inch. Thus, film 8A resulted in a lower initial peel strength comparedto the initial peel strength of comparative film 8B. The reclose peelstrength of film 8A after 4 cycles and after 7 cycles was comparable tothe reclose peel strength of comparative film 8B that included theadhesive composition of Comparative Example 2. The results measuredafter heat sealing at 150° C. exhibited a similar comparativerelationship to the films prepared at a heat sealing temperature of 130°C. These results for film 8A and comparative film 8B indicate that thefilm 8A requires a lesser initial opening force compared to comparativefilm 8B, but would provide equivalent reclose performance. Therefore,film 8A would be easier to initially open compared to comparative film8B, but would provide equivalent reclose strength to comparative film8B.

Comparative film 8C included the adhesive composition of ComparativeExample 3, which included only 33.4 wt. % of the ethylene/α-olefin blockcopolymer and 30 wt. % styrenic block copolymer. Thus, Layer B ofcomparative film 8C had an increased proportion of styrenic blockcopolymer and decreased amount of ethylene/α-olefin block copolymercompared to Layer B of comparative film 8B and film 8A. As shown by theresults in Table 6, increasing the amount of the styrenic blockcopolymer in Layer B reduces the initial peel strength of thecomparative film 8C compared to the initial peel strength of film 8A.However, the increased amount of styrenic block copolymer in Layer B ofcomparative film 8C was observed to degrade the reclose peel strengthperformance of comparative film 8C compared to the reclose peel strengthof film 8A. The degradation in the reclose peel strength performance ofcomparative film 8C is more pronounced after sealing comparative example8C at the seal temperature of 150° C. Although increasing the amount ofstyrenic block copolymer in Layer B, such as with comparative film 8C,may decrease the initial peel strength and make the film easier to open,increasing the amount of the styrenic block copolymer in Layer B mayadversely affect the reclose peel strength, resulting in weaker recloseseal strength and a reduction in the number of reclose cycles possiblefor the film. Thus, film 8A that included the composition of Example 1in Layer B may provide better reclose performance compared to thecomparative film 8C, which included an increased amount of styrenicblock copolymer in Layer B.

Film 8A has a lesser amount of styrenic block copolymer in Layer Bcompared with comparative films 8C and 8D. Therefore, film 8A mayprovide reclose functionality to food packaging without impacting theodor and/or taste of the food products packaged therein.

1. A reclosable package comprising: a front wall, a rear wall, and abottom of the package; and a closure region proximate to an outer edgeof the package opposite the bottom, the closure region comprising aplurality of seal regions forming a continuous seal between the frontwall and the rear wall across a width of the package, wherein at leastone of the seal regions is nonlinear and the closure region comprises atleast one unsealed region defined between the seal regions.
 2. Thereclosable package of claim 1, wherein the closure region furthercomprises two or more seal lines, wherein a seal line is a linearcontinuous seal between the front wall and the rear wall, across thewidth of the container.
 3. The reclosable package of claim 2, whereinthe two or more seal lines comprise an upper seal line, the seal linefarthest from the bottom, and a lower seal line, the seal line closestto the bottom and the at least one nonlinear seal region is disposedbetween the upper seal line and the lower seal line.
 4. The reclosablepackage of claim 1, wherein the application of an opening forceproximate to the closure region is operable to separate at least part ofthe front wall from the rear wall, breaking the continuous seal betweenthe front wall and the rear wall across a width of the package.
 5. Thereclosable package of claim 4, wherein, after separating at least partof the front wall from the rear wall, contacting the front wall to therear wall proximate to the closure region and applying a closingpressure proximate to the closure region is operable to reform the sealbetween the front wall to the rear wall across a width.
 6. Thereclosable package of claim 1, wherein the closure region comprises arepeating geometric pattern of seal regions.
 7. The reclosable packageof claim 1, wherein the closure region comprises a reclose film.
 8. Thereclosable package of claim 1, wherein at least one seal regioncomprises a reclose film.
 9. The reclosable package of claim 1, whereinthe front wall, the rear wall, or both, comprise a flexible film. 10.The reclosable package of claim 1, wherein at least one seal regioncomprises at least three layers and the at least three layers include: asealant layer comprising a top facial surface and a bottom facialsurface; a reclose layer, comprising a top facial surface, a bottomfacial surface, and an adhesive; at least one outer layer comprising atop facial surface; wherein: the reclose layer is disposed between thesealing layer and the at least one outer layer; the top facial surfaceof the reclose layer is in adhering contact with the bottom facialsurface of the sealant layer; and the bottom facial surface of thereclose layer is in adhering contact with the top facial surface of theat least one outer layer.
 11. The reclosable package of claim 1, whereinat least one seal region comprises an adhesive comprising: anethylene/α-olefin random copolymer; and a styrenic block copolymercomprising from greater than 1 wt. % to less than 50 wt. % units ofpolymerized styrene; a tackifier; and an oil.
 12. The reclosable packageof claim 11, wherein the adhesive comprises: from 30 wt. % to 65 wt. %of the ethylene/α-olefin random copolymer; from 10 wt. % to 35 wt. % ofthe styrenic block copolymer; from 20 wt. % to 40 wt. % of a tackifier;and from greater than 0 wt. % to 8 wt. % of an oil.